Pragma-hack: remote computer rebooter.
This probably looks April-Fool-y, but it's not a joke.
The gist: Old electro-mechanical, cassette-based answering machine repurposed to reboot a computer up in a cabin in Maine.
Status: Recently replaced by an X-10 set after about seven years of service.
This thing is on the same phone line as the modem that the old Win2k computer uses to dial out and push weather-station and webcam data to the 'Net. If I see that the data aren't coming, the most likely reason is that the computer has frozen. (Figuratively, not literally, even though it is pretty far "up Maine.")
When I call the cabin, either the modem answers the phone on the first ring (and I can jack in by pcAnywhere or the like) OR the computer is frozen and needs a reboot. After five rings, the answering machine answers. (Note, for the sake of clarity, that if the modem picks up, the answering machine never hears five rings, and never answers, and doesn't cause a reboot.)
When the answering machine answers, it plays the outgoing message, and as long as the outgoing message plays, a microswitch (near the play head mechanism) is depressed. That microswitch is connected to an NO relay on the AC line to the power strip. Thus, as long as the OGM is playing, the power is cut to the PC (plugged in to the power strip), and when the OGM is finished (about 30 sec), the power is restored to the PC, and up it boots.
Cheap and very effective, this remote rebooter was in service for about seven years. In order to control a few other devices, I recently replaced it with an X-10 phone interface and a few X-10 modules.
Past features. - Back